Various fruit juices and beverages that contain fruit juice are very popular because of their appealing taste and also because they are perceived as being natural and nutritious. Commercially extracted and packaged fruit juices have enjoyed wide commercial success because of their convenience. However, it has been found that many consumers generally prefer the taste of hand-squeezed juice over commercially processed juice. Accordingly, a principal object of the present invention is to extract in a commercial environment the edible components of a fruit, particularly the juice and juice sacs, such that they have a taste similar to that of hand-squeezed.
Citrus fruits such as oranges, grapefruits, tangerines, lemons, and limes basically consist of an outer colored peel (flavedo), an inner white spongy peel (albedo), and the inner meat formed in wedge-shaped segments that are separated by a fibrous membrane commonly referred to as "rag." The fruit also includes a pulpy core that contains several large and small seeds. The individual meat segments primarily consist of juice sacs, which are elongated or oval-shaped sacs that contain fruit juice and are held together by an epicuticular wax. In general, the fruit's juice sacs and juice are considered to be the most desirable components for human consumption purposes. The fruit's other components, i.e., the peel, rag, and seeds, are very useful for other applications such as cattle feed.
The method used in extracting the edible components of a fruit greatly influences the final product's taste, texture, and overall quality. Generally, it has been observed that the cleaner, quicker, and more gently the fruit's juice and juice sacs are separated from the fruit's other components, the less the juice comes into contact and mixes with undesirable flavor elements, which include naringin, .alpha.-terpineol, linalool, and d-carvone that are found in the peel; and limonin that is found in the seeds and membranes.
During hand squeezing, the consumer either intuitively or because of physical limitations presses lightly on the fruit which results in juice having less undesirable flavors than found in commercially extracted juice. This gentle pressure is difficult and not cost effective to duplicate in a mass production setting where high yields are absolutely critical. Indeed, most production machines in wide use today for extracting fruit juice can perhaps be most accurately characterized as fruit smashers. These machines essentially break the fruit into its various components and subsequently separate them by, for example, forceful screening, an example of which is the apparatus disclosed in U.S. Pat. No. 4,700,620 and leased by the FMC Corporation. During the bashing and separating steps, the fruit's components undergo much abrading and co-mingling, thus releasing and mixing the undesirable flavor elements that are found in the peel, membranes, and seeds with the juice. In addition, such rough handling essentially guarantees that none of the fragile juice sacs will survive intact.
Another type of apparatus used in the commercial juice extracting industry can be generally characterized as a reamer, examples of which are disclosed in U.S. Pat. Nos. 2,737,989 to Wurgaft and 4,479,424 to Carroll. In a basic reaming operation, the fruit is first cut in half, followed by pressing a reaming element into the exposed fruit meat to extract the juice. In general, it has been found that this type of extraction method produces low quality juice because the reaming element also squeezes the peel, membranes, and seeds, thereby releasing the undesirable flavor components found in each. In addition, in the case of a citrus fruit, the sectional membranes tend to fold over on top of one another when the reamer is forced into the fruit half, thereby making it extremely difficult to extract the fruit meat and juice deep within the fruit half. Indeed, because of the critical need for high yields in a commercial operation, most extractors find it necessary to press the reaming element very hard into the fruit which further aggravates the problem.
Another type of fruit extraction method and apparatus is generally referred to as a peeler, an example of which is disclosed in U.S Pat. No. 3,700,017 to Vincent et al. In such a system, an oriented fruit is placed between two spikes that are sharply shoved into the stem ends of the peel. The spikes and attached fruit are then rotated while two knives move laterally across the rotating fruit to cut the peel from the meat. Although such a system does effectively extract fruit meat from the fruit, it has been found that cutting the peel in this fashion releases a substantial amount of the undesirable flavor components found therein which contaminates the strong spike/peel connection to maintain a high peeling torque, which in turn requires the critical orienting step in order to insert the spike into the fruit's stem area where the peel thickness is greatest.
Another type of extraction system involves using various chemical baths such as alkali/phosphate or acid to dissolve the sectional membranes, examples of which include U.S. Pat. No. 4,560,572 to Watanabe and U.S. Pat. No. 4,139,651 to Sekiguchi. However, it is believed that such systems would be extremely unattractive in a commercial environment because of the high costs associated with the necessary chemicals. In addition, it is believed that the chemicals used in such processes would have a major adverse effect on the fruit juice's taste.
Still another extraction technique involves using high pressure fluid jets, examples of which include U.S. Pat. Nos. 1,982,741 to Keenan, 4,294,861 to Ifuku et al., and 4,300,448 to Hayashi et al. Generally, this type of system includes the critical steps of orienting the fruit relative to its stem and cutting the fruit in half perpendicular to the stem, followed by placing the exposed fruit meat in front of a fluid jet nozzle. High pressure fluid emitted from the nozzle blasts the juice and fruit meat from the peel. However, it has been found that this type of extracting system is commercially unattractive because of the large volume of pressurized fluid required to extract a commercially acceptable yield. In addition, as with reaming, the sectional membranes tend to fold over and impede the emitted fluid's ability to remove the meat deepest within the peel.
With virtually all methods and apparatuses used to extract juice and fruit meat from a fruit, a certain percentage of the fruit's seeds are also extracted that must be removed. One common apparatus used for removing seeds is a liquid cyclone or hydroclone that relies on differences in densities to separate materials. In operation, juice containing seeds tangentially enters an inverted cone at a very high speed and forms a vortex. The centrifugal force of the vortex throws denser materials out near the cone's inner surface. These dense materials, which are mostly seeds, become concentrated near the cone's pointed bottom section and are removed as underflow. Lighter materials rise inside the cone and are removed as overflow. However, it has been observed that many seeds have densities very similar to juice sacs and therefore cannot be separated by using this method.
In light of the above, the principal object of the present invention is to separate and remove seeds found in a slurry comprised of juice and unruptured juice sacs while rupturing a minimal amount of the juice sacs.
Another principal object of the present invention is to extract fruit meat from a fruit without rupturing a substantial portion of the fragile juice sacs.
Another principal object of the present invention is to extract fruit meat and juice from a fruit without extracting undesirable flavor elements from the peel, membranes, and seeds.
Yet another object of the present invention is to achieve high juice yields in a commercial environment.
Another object of the present invention is to extract large pieces of fruit meat from a fruit that can be subsequently separated into unruptured juice sacs and juice.
Another object of the present invention is to extract a very substantial portion of the fruit meat and juice from a whole fruit while exerting little pressure on the fruit's peel.
A further object of the present invention is to separate a substantial amount of unruptured juice sacs from the sectional membranes or rag of a large chunk of fruit meat that was extracted from a fruit.